From an article on the psychology of fanaticism:

"A fanatic is one who can't change his mind and won't change the subject."      –Winston Churchill

According to the article, Conrad, however, is not a true fanatic.

"A fanatic differs from a crank in that the latter term is typically associated with a position or opinion which is so far from the norm as to appear ludicrous and/or provably wrong."

FYI.

Don Firth